In the first ruling of its kind, a judge in Mexico has granted two people the right to use cocaine recreationally, the organisation behind the cases said on Tuesday, calling it a "historic step".
The ruling, which must be reviewed by a higher court, allowed the two petitioners to "possess, transport and use cocaine", but not to sell it, according to Mexico United Against Crime, an organisation devoted to ending the country's "war on drugs".
The Mexico City court ordered the national health regulator, COFEPRIS, to authorise the petitioners' cocaine use in personal, recreational doses, the organisation said.
However, a COFEPRIS official told AFP news agency that the regulator has moved to block the court order, which was delivered in May, arguing that issuing such authorisation would be outside its legal remit.
The ruling will only take effect if the higher court sides with the original decision, and would only apply to the two people who brought the cases, whose names were not disclosed.
"This case represents another step in the fight to construct alternative drug policies that allow [Mexico] to redirect its security efforts and better address public health," Mexico United Against Crime said in a statement.
"We have spent years working for a more secure, just and peaceful Mexico. This case is about insisting on the need to stop criminalising ... drug users and designing better public policies that explore all the available options," said the group's director, Lisa Sanchez.
Mexico has been moving slowly away from its strict prohibitionist drug policies in recent years.
The country's Supreme Court has authorised recreational cannabis use in individual cases, including one brought by the Hollywood actor, Diego Luna.
Mexico's leftist President Andres Manuel Lopez Obrador has repeatedly said the country should evaluate decriminalising drugs. His party, Morena, has introduced a bill in Congress to legalise recreational cannabis use.
Mexico has been hit by a wave of violence since the government deployed the army to fight the country's powerful drug cartels in 2006.
Since then, more than 250,000 people have been murdered, including a record 33,755 last year.